Closure cap, especially for closing the connection of an oil filter

ABSTRACT

The invention relates to a closure cap, especially for closing a screw neck of an oil filter connection in motor vehicles. An elastically expandable nut element ( 5,20 ) is arranged in the closure cap. Said nut element is such that it can be placed on screw necks ( 3 ) of various diameters, engaging with the outer thread of the screw neck.

The invention relates to a closure cap which is especially provided forclosing an oil filter connection in motor vehicles.

When disposing of old vehicles, the oil in the engine is drawn off andthe oil filter is screwed off. However, old oil remains in hollow spacesin the engine and can run out through the oil filter connection duringthe further handling of the engine. Therefore, a closure cap is mountedon the oil filter connection. As the screw necks of oil filterconnections have different diameters according to the different types ofvehicle, different sizes of closure cap must be provided.

The invention is based on the object of designing a closure cap suchthat screw necks of different diameter can be reliably sealed.

This object is solved according to the invention by a closure capaccording to claim 1. Because the closure cap has an elasticallyexpandable nut element, the closure cap can be screwed onto screw necksof different diameter, so that only one closure cap needs to be providedfor different types of vehicle.

The invention is exemplarily explained in more detail with reference tothe drawing, in which

FIG. 1 shows a section of a closure cap screwed onto a screw neck;

FIG. 2 shows a perspective view of the nut element insertable in theclosure cap over a screw neck of an oil filter connection;

FIG. 3 shows a modified embodiment of a nut element;

FIG. 4 shows a partial longitudinal section along the line I-I in FIG. 5through a plastic cap without an inserted spring clip;

FIG. 5 shows a view of the closure cap in FIG. 4 from below;

FIG. 6 shows a sectional view along the line II-II in FIG. 5;

FIG. 7 shows a preferred embodiment of a closure cap having an insertedspring clip;

FIG. 8 shows a view of the closure cap in FIG. 7 from below;

FIG. 9 shows a perspective view of the closure cap according to FIGS. 7and 8 from below;

FIG. 10 shows another embodiment of an expandable nut element; and

FIG. 11 shows a further embodiment of a cap.

The approximately hat-shaped closure cap 1 consists preferably ofplastic and has a flange portion 2 which comes to bear on a surface 3 asurrounding the screw neck 3. On the flange portion 2, a ring seal 4 isprovided which seals the screw neck 3 to prevent leakage of oil afterthe closure cap 1 has been screwed onto the screw neck 3.

In the closure cap 1, inserted in diametrically opposite groovesextending in an axial direction is a nut element 5 in the form of aspring clip shown in FIG. 2, having an elastically expandable screwengaging portion 6 on diametrically opposite spring arms 7. In theembodiment shown, the free ends of the spring arms 7 are bent inwards togive inclined surfaces 8 which merge into a horizontal section 9, whichextends radially outward. From each radially outward end of thehorizontal section 9, a portion 10 is bent inward, which also extendsapproximately horizontally, that is, approximately to the longitudinalaxis, and is positioned somewhat inclined in relation to thelongitudinal axis, so that the free edge of the portion 10 correspondsto a section of a thread. Preferably, the edge of the portion 10 isformed arc-shaped in the view along the axis of the closure cap.

On mounting the closure cap on a section of thread, first the inclinedsurfaces 8 come to bear on the outer circumference of the screw neck 3,whereupon, when the closure cap 1 is pressed on, the lower ends of thespring arms 7 are displaced radially outwards until the engaging portion10 can engage with the thread on the outer circumference of the screwneck 3. For this purpose, the free edge of the portion 10 protrudesbeyond the inner edge of the inclined surface 8. After that, the closurecap is screwed on until the flange portion 2 having the ring seal 4comes to bear on the surface 3 a.

The seal of the screw neck 3 can be formed by inserting an oil retainerring on the inside of the closure cap 1, for example in the area of thestay 5′ of the spring clip. Preferably, the seal is provided on theoutside of the closure cap on the flange portion 2 in the form of thering seal 4, so that the seal is independent of the diameter of thescrew neck 3 and the functioning of the elastically expandable nutelement 5 is not hindered.

Different modifications of the described embodiment are possible. Forexample, instead of a two-arm spring clip 5, a nut element can also beprovided which has a plurality of elastically deformable arms which aredistributed over the circumference and which are provided with one or aplurality of engaging portions.

The stay section 5′ of the approximately U-shaped spring clip formedfrom a strip of resilient material can serve to fix the spring clip inthe closure cap, for example by riveting or bonding. Preferably the arms7 of the spring clip are additionally guided in longitudinal grooves 16(FIG. 4) on the inner circumference of the closure cap so that they arejoined to it in such a way as to avoid rotation.

On the outside of the closure cap, a hexagon step 11 can be formed sothat a tool for screwing on the closure cap can be attached.

Instead of the thread engaging portion 10 on the spring clip 5, theinside edge of the inclined surface 8 can also be designed as anengaging portion, as FIG. 3 shows schematically for a plastic clip,whose diametrically opposite arms 7 have triangular ribs 12 which can bedisplaced radially outwards in the direction of the arrows to be able toengage with the thread.

FIG. 7 shows an embodiment having a spring clip 5 in which the threadengaging portion 10 is formed by a bending of the free edge of theinclined surface 8.

FIG. 4 shows in a partial longitudinal section a plastic cap 13 alongthe line I-I in FIG. 5, in which on the outer edge of the flange portion2 a plastic sealing lip 4′ is formed. Instead of the sealing lip 4′, anO-ring can also be inserted in a groove of the plastic. A recess 14 isprovided on the inside for inserting the spring clip 5. Plasticprojections 15 are provided at opposite positions in this recess 14, andon these the stay section 5′ of the spring clip snaps in by pressing, sothat a separate connecting element is not required.

In FIGS. 4 and 5, lateral guide grooves 16 for the spring arms 7 (FIG.2) are provided, by which the spring clip 5 is held in a rotation-proofway in the cap 13.

FIG. 6 shows in a sectional view rotated by 45° along the line II-II inFIG. 5 diametrically opposite plastic lips 17 which merely serve forcentring a screw neck having a small diameter. When a closure cap ismounted on a screw neck having a small diameter, these plastic lips 17are displaced to the side, wherein they can also break off. They servemerely as a threading aid.

In the embodiment of a plastic cap 13 shown in FIGS. 4 to 6, thecylindrical inside designated 18 is designed such that it can receivethe largest diameter of a screw neck. The engaging sections 8, 10 of thespring arms 7 in the grooves 16 here extend into the cylindrical hollowspace 18, so that they can also engage with a screw neck having asmaller diameter.

FIGS. 7 to 9 show a preferred embodiment of a closure cap, wherein onthe inside of the front wall 24 of the plastic cap 13 which istransverse to the longitudinal axis, a pin 25 is formed on which thespring clip 5 is mounted. For this purpose, the spring clip has on thestay portion 5′ a bore for receiving the pin 25. Preferably a snap-inconnection is provided so that the spring clip mounted on the pin 25cannot fall out when the closure cap is being handled. It is alsopossible, instead of providing a round pin, to provide a polygonal crosssection of the pin, so that additionally to the holding function, arotation-proofing of the spring clip relative to the cap is achieved.Additionally, however, the spring clip is guarded from twisting relativeto the cap by the spring arms 7 in the grooves 16.

In FIG. 7, the left spring arm 7 is shown in a starting position inwhich the engaging portion 10 engages with the outer thread of a screwneck 3 having a minimum diameter, while the right spring arm 7 in FIG. 7is shown in a position in which it engages with the thread of a screwneck having a maximum diameter. FIG. 8 also shows in a view from belowin FIG. 7 these two end positions of the spring clip, wherein the bentedge of the engaging portion 10 is also shown which is also recognizablein the perspective view of the closure cap in FIG. 9 from below.

Preferably, the spring arms 7 in the engaging area are formedapproximately V-shaped between the inclined surface 8 and a bent portion7′, as FIG. 7 shows, to improve the elasticity in the engaging area.Hereby, the radially outward area of spring ams 7 can abut on the innerwall of the groove 16 when a maximum diameter of a screw neck 3 isreceived, as the right-hand side in FIG. 7 shows, wherein due to theV-shape of the engaging portion, sufficient elasticity still exists forengagement on the screw neck.

FIG. 10 shows a nut element 20 which is insertable in a closure cap andwhich consists of a hollow, truncated cone-shaped, injection-moldedplastic part. A base ring 21 corresponding to the largest diameter of ascrew neck and which does not need to be expanded when screwed on, hason its inner circumference two or three threads on a cylindricalportion, so that this base ring 21 can be directly screwed onto a screwneck having the largest diameter. The circumferential surfaces 22 whichstart from the base ring 21 and are distributed over the circumference,have on their inner circumference a thread, wherein the individualportions are separated from one another by slits 23, so that duringmounting on a screw neck having a medium diameter, the edge of the screwneck comes to bear approximately in the middle area of this nut element,whereupon the circumferential sections 22 are displaced outward in thedirection of the arrows when the nut element 20 is screwed onto thescrew neck.

The nut element 20 can, for example, be inserted and fixed in a plasticcap by means of a bayonet joint or the like. However, an expandableplastic nut element 20 can also be formed directly on a plastic cap 13.

An essential advantage of a closure cap of the described type consistsin that, due to the expandable nut element, the closure cap can bepressed so far down onto the respective screw neck that the flangeportion 2 having the surrounding seal abuts on the circumferentialsurface of the screw neck, whereupon only one additional twisting of thescrew with one to two rotations is required to tighten the closure capand firmly press on the flange portion 2.

According to a further embodiment, the elastically expandable nutelement can also be formed as a catch element, so that the plastic capmerely needs to be pressed onto the screw neck to be sealed, wherein thecatches corresponding to the thread portions 10 engage with the outerthread of the screw neck and hold the closure cap in the pressed-onposition.

In order that reliable sealing is achieved for this embodiment, theflange portion surrounding the closure cap is formed elastically andpreferably provided with a prestress. FIG. 11 shows an embodiment of anapproximately truncated cone-shaped flange portion 2′ formed on andhaving a formed-on sealing lip or an O-ring 4 inserted in a groove. Whenpressing the closure cap onto the screw neck, the conic flange portionis deformed into an approximately horizontal position, so that thesealing lip abuts closely under prestress on the surface surrounding thescrew neck, while the catch element inside the closure cap holds theclosure cap in the prestressed position.

The catch element can be formed as a spring clip according to FIG. 2,wherein, instead of the engaging portions 10, simple catches can beprovided.

The spring clip can be made of spring steel whereas the cap is made ofplastic material. The spring clip can also be made of sufficientlystrong elastic material.

1. Closure cap, especially for closing the screw neck of an oil filterconnection in motor vehicles, wherein in the closure cap an elasticallyexpandable nut element is arranged, which is suitable for being mountedon screw necks of different diameter, such that the nut element engageswith the outer thread of a screw neck, wherein the nut element isdesigned in the form of a two- or multi-arm spring clip formed from astrip of resilient material which is positioned in a rotation-proof wayin the closure cap and has spring arms for engagement in the thread of ascrew neck, wherein on free ends of the spring arms, a portion is bentinwards for forming an inclined surface, to which a horizontal portionis connected whose free edge is inclined relative to the longitudinalaxis for engagement with the thread of a screw neck.
 2. Closure capaccording to claim 1, wherein a flange portion provided with a ring sealis provided with prestress in the axial direction, wherein the flangeportion comes to bear on the surface surrounding the screw neck. 3.Closure cap according to claim 2, wherein the flange portion is formedconically and is elastically deformable.
 4. Closure cap according toclaim 1, wherein a flange portion is provided which comes to bear on thesurface surrounding the screw neck and has a ring seal.
 5. Closure capaccording to claim 1, wherein the spring arms are positioned inward fromthe inner surface of the cap to form an air gap between the spring armsand the inner surface of the cap to allow radial motion depending on thediameter of the screw neck when engaging the thread of the screw neck.